Thinking of buying a XFX 6950 for a new rig mostly so I can bios hack it to 6970 performance, good idea or bad idea?

I currently have a MSI twin frozr ii gtx 470 which is great but I use higher resolutions than most and for some reason I cant fit two DVI's + 1 hdmi adapter all in to the back with a Corsair Graphite 600T

6950 is going to get a fix in a batch which removes the possibility of an unlock. I'm unaware when this is going to happen but it's been a reality for a week or two now so you may get unlucky and find yourself with a newer batch version which doesn't have the unlock ability.

Any recommendations for block cooling for the unit, hopefully nothing over $99 otherwise might as well get a 6970

You really don't have a lot of options for under $100. Personally I am going to cheap out this time around and go w/ Swiftech MCW80's plus stick on heatsinks. I am sick of losing $50-$75 a block every few months when I try to sell them.

You really don't have a lot of options for under $100. Personally I am going to cheap out this time around and go w/ Swiftech MCW80's plus stick on heatsinks. I am sick of losing $50-$75 a block every few months when I try to sell them.

So if you were me, what would you consider installing (custom cooling) on this unit if you intend to keep it around for 2-3 years minimum with a decent amount of use, maybe 20-40 hours of heavy use a week

You doing this for silence or performance? You can always increase your stock fan speed and it will stay cool. Or you could just wait a few months and we will start to see better air coolers available.